Muscle quality decline and fat infiltration in non-elderly OSA patients: associations with metabolic abnormalities

Obstructive sleep apnea (OSA) and adverse muscle alterations are significant age-related disorders associated with cardiovascular and metabolic morbidities. However, their relationship in non-elderly populations remains unclear.

This study enrolled 52 hypertensive patients aged below 60 years (mean age: 48.5 ± 7.6 years), divided into OSA (n = 29, apnea-hypopnea index [AHI]  ≥ 5) and control (n = 23) groups. Muscle quantity (erector spinae muscle [ESM] cross-sectional area [CSA], normalized CSA indices: CSA/height², CSA/BMI) and quality (muscle density, radiographic density ratio [RDR], fat infiltration rate [FIR]) were assessed via chest CT. Plasma metabolites were analyzed using untargeted metabolomics.

The OSA group had higher BMI (27.3 ± 4.3 vs 24.8 ± 3.2 kg/m², p = 0.02) and larger ESM CSA (20.6 ± 5.8 vs 15.8 ± 5.1 cm², p = 0.003), CSA/height² (6.9 ± 1.8 vs 5.5 ± 1.4, p = 0.003), and CSA/BMI (0.75 ± 0.17 vs 0.63 ± 0.17, p = 0.018) compared to controls. Muscle density (35.3 ± 7.5 vs 41.6 ± 4.7 Hounsfield units, p = 0.001) and RDR (1.5 ± 0.6 vs 2.3 ± 0.5, p < 0.001) were lower, while FIR was higher (9.6 ± 3.6% vs 3.5 ± 1.8%, p < 0.001) in the OSA group. A subgroup analysis including only patients with normal BMI yielded similar results. Metabolomics revealed 13 differentially expressed metabolites, with Anserine, Adipic acid, and Mestranol positively correlated with FIR.

OSA is associated with reduced muscle quality and increased fat infiltration in non-elderly hypertensive patients, and linked to metabolic abnormalities.